Optimization of Cutter Geometry Features to Minimise Cutting Force on Machining Polyetheretherketone (PEEK) Engineering Plastic

Abstract

Machining of thermoplastic material poses several challenges due to its low melting temperature and high thermal expansion which directly related to cutting force. Thus, controlling the cutting force and temperature is desirable for machining polyetheretherketone (PEEK). The cutting force is dependent on friction and shearing action produced by the tool. It is indicated the cutting force is significantly affected by tool cutter geometry. This paper aims to control the cutting force by optimizing the cutter geometries especially rake, clearance and helix angle on machining PEEK. The two –flutes of solid carbide ball nose end mills were used to conduct the experiments and the cutting force acquired was measured using piezoelectric dynamometer. Response Surface Methodology (RSM) approach was applied to design and analyse the optimal combination of tool geometry feature for machining PEEK. Based on obtained results, the best optimal values of tool geometry which contribute to minimum of cutting force were 17° rake angle, 26° of helix angle and 10° of clearance angle. The best control of tool geometry ultimately improves the cutting performance and reduces defect caused by high cutting forces.